Modern replacements for CA3140 and NE531 (Scamp S04 EQ)

[user 40373]

I have several Scamp S04 EQs with various issues. 2 work except for the mid band, and one doesn't pass signal.

These use either CA3140 or NE531 op amps and they must be able to be used interchangeably because between the 3 modules with issues they are swapped around.

What is a modern drop in replacement? Unfortunately I can't find the schematic for the S04 anywhere.

 

[JohnRoberts]

The CA3140 is old BiMos op amp... I suspect a modern bifet (something like TL071) would probably make a suitable replacement. NE531 is a high slew rate old bipolar, for reproducing audio we don't need 35 V/uSec. A ne5534 would probably be adequate. There are any number of modern replacements.

JR

 

[mjrippe]

Schematics are attached. If you want to stick with the originals, the CA3140 is still available. Well, Mouser and Digikey don't have them in stock but they are still an active part number. I have some I can spare if you want to DM me.

 

[user 40373]

Schematics are attached. If you want to stick with the originals, the CA3140 is still available. Well, Mouser and Digikey don't have them in stock but they are still an active part number. I have some I can spare if you want to DM me.

Thanks for the schematic that's a huge help! I tracked down some RCA CA3140 on eBay. Do you have any other Scamp schematics?

 

[mjrippe]

Thanks for the schematic that's a huge help! I tracked down some RCA CA3140 on eBay. Do you have any other Scamp schematics?

A couple, what else are you looking for?

 

[user 40373]

Just the S23 Panner...I think I have schematics for the other modules I own.

 

[mjrippe]

Got it, too big to post here though. I put it up on DropBox here:Scamp_S23_Panner.pdf
And the Log Amp cal and schematic are here: Scamp_S23_Log_Amp.pdf